This section provides background information related to the present disclosure, which is not necessarily prior art.
Flow of refrigerant through an evaporator of an air conditioning system is often controlled by a thermal expansion valve (TXV) located within a TXV housing. The TXV meters flow of refrigerant to the evaporator based on temperature of the refrigerant that has passed through the evaporator, as sensed by a sensor bulb. TXVs are typically located in close proximity to the evaporator for the best possible air-conditioning performance. To facilitate servicing, TXVs are also typically located at a vehicle dash-wall, and coupled to the evaporator with metal tubes.
When the air conditioning is initially activated, due to lack of sufficient sub-cooling, gaseous or gas/liquid refrigerant at high pressure passes through a small orifice of the TXV resulting in high velocity refrigerant that readily excites the acoustical cavity modes and circular/cylindrical higher order modes of refrigerant system components, which results in undesirable noises being produced, such as transient/audible hiss and gurgle. With existing TXVs, heavy damping material layers are applied to the TXV, tubing, and evaporator in an attempt to suppress the undesirable noises. Application of these damping materials suppresses hiss and some compressor induced noises. However, use of damping materials often undesirably results in amplification of transient gurgle when the air conditioning is turned on, and after the air conditioning has been turned off. Use of damping materials is thus undesirable because they can add cost and weight, are difficult to apply consistently, and induce and/or amplify gurgle noises. It would therefore be desirable to provide an improved device and system for suppressing undesirable gurgle that may occur when an air conditioning system is initially activated. The present teachings address these needs, as well as numerous others, and provide improvements over the art.